1. Field of Invention
This invention relates to clamping devices for attaching a sign or other display means to a post or other upright support. More specifically, the present invention relates to sign clamps which have converging halves which cooperate to surround a support post and clamp the sign thereto by fixation of the sign to one of the clamp members.
2. Prior Art
A variety of devices and methods have been developed over the past years for attaching a sign or display means to an upright post or sign support. Where the sign support is a free standing structure such as a post, tube, channel or other upright support structure which supports circumferential attachment of a clamp around the post, numerous devices have been developed. For example, a circular clamp which attaches at its periphery to the sign and is bolted directly to the sign post or support structure is well known. Typically, such mounting configurations involve drilling a hole through the support post or otherwise securing the screw or bolt within the post structure. Although such a technique is suitable in some instances, concrete posts or other support structures which are very difficult to penetrate poses a difficult challenge. Furthermore, where signs are changed periodically, new holes must be drilled, thereby weakening the sign support or defacing its appearance.
Other circumscribing attachment devices have been developed which represent a pair of circular clamps, open at one side and including projecting flange members which enable joining at the flanges by a bolt and nut. Typically, the inner diameter of the clamp is less than the outer diameter of the post. In such instances, the forces retaining the attachment device at the sign post are tangential forces along the post exterior which are applied by tightening the respective flanges into close contact, thereby squeezing the sign post within the shortened diameter. This necessitates appropriate sizing of the clamp to properly grasp the sign post at internal faces of the clamp structure.
Such a configuration involves application of direct forces applied by pulling the two clamp halves into close relationship. Naturally, application of such direct forces require the use of bolts or other structure which restrains the clamp halves bidirectionally, both toward the joining faces of the clamps, as well as at opposing orientations directed away from the clamp faces. Such clamping structures are typically more cumbersome to install and detach and are frequently subject to deformation around the post by virtue of the forces applied at each side of the clamp. Furthermore, the use of bolts on opposite sides of the clamp requires some balancing of force between the opposing bolts. This balancing must be accomplished by placing the approximate same number of turns with respect to each bolt, thereby maintaining an approximate common separation distance between the opposing clamp members.
These complications characterize the typical problems associated with clamping structures for signs. These problems generally involve difficulty of attachment, labor intensive procedures for attachment to the post and fabrication procedures which tend to be costly where several components make up a single clamp structure. What is needed is a general clamp configuration which reduces fabrication cost and labor and provides simple installation technique which is versatile with respect to any sign post requiring circumferential attachment of the sign and the attached clamp structure.